Charles spiro



NrTnD STATES PATENT FFICE.

CHARLES SPIRO, OF NEIV YORK, N. Y.

PHOTOGRAPHIC DEVELOPING-BATH.

SPECIFICATION forming part of Letters Patent No. 409,618, dated August 20, 1889.

Application filed February 12, 1889x Serial No. 299,608- (No specimens.)

T0 aZZ 1071 0117, it may concern:

Be it known that 1, CHARLES SPIRO, a citizen of the United States, and a resident of the city of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Photographic Developing-Baths, of which the following is a specification.

This invention relates to means for developing the latent images of photographic plates or sheets without a dark-room, and has for its object to provide a developing-mixture whereby a complete isolation of the developing photographic plate or sheet will be secured from the actinic rays of light, while a clear view of the developing-image may be obtained.

In developing a photographic plate or sheet in a dark-room, as heretofore, in which the only light was the dim light admitted through ruby or orange colored glass used to exclude the actinic rays, it was possible for the operator to watch the progress of and control the development only by removing the plate or sheet from the developingbath from time to time and holding it up to the light for inspection, which process was wearisome and in many instances destructive to the plate, owing to the incomplete exclusion of the actinic rays and the, perhaps, extreme sensitiveness of the plate. To avoid these inconvenlences and attain the objects of my invention, I provide a mixture consisting of any of the ordinary and well-known developers, such as pyrogallic acid and soda or hydroquinnone, in combination wit-l1 a non-actinic inorganic coloring-matter, preferably orange aniline, or a mixture of the same and carmine aniline, where the plate or sheet to be developed is very sensitive. In preparing this non-actinic developing-mixture at present I take, preferably, hydroquinnone for the developer, and to one pintthereof I add a so lution composed of equal parts of alcohol and water (to energize the solution) to make one ounce and two parts of orange aniline and one pint of carmine to make half an ounce, thoroughly mixed together and dissolved, so as to form a co1npletely-saturated and darkorange colored solution of diluted alcohol. This solution is first well strained to remove all extraneous matter and then combined with the developer, as before stated. This mixture is poured into a developingtray and the pl'lotographic plate or sheet to be developed transferred from the plate-holder into the non-actinie bath thus prepared either in the dark room, afterward admitting the light thereinto or removing the bath with the contained plate into the light, or by any Wellknown or approved means for eifecting this transfer in the light without exposing the plate or sheet thereto. The non-actinic bath will completely exclude the actinic rays from the immersed plate or sheet, and the developing-mixture being perfectly clear the development will proceed in full view of the 0perator, who may thus easily note the progress of the development. W hen the image is found to be fully developed, the plate or sheet may be transferred in the light to a bath of any of the usual fixing agents-such as hyposulphite of soda-and the bath quickly covered with a dark cloth; or the fixing-bath may be likewise rendered non-actinic by the addition thereto of the same non-actinie coloringmatter. The transfer of the developed plate or sheet from the non-actinic developing-bath into the fixing-bath in the light may be thus effected without clouding the image, insomuch as the aniline coloring-matter, as well as all other inorganic coloring-matters, so far as known, forms a perfect solution and fills the pores of the gelatine film, so as to form a perfectly non-actinic envelope over the film, lasting until the plate is immersed in the fixingbath. The fixing action then immediately commencing, light has no further effect on the film.

The proportions of the developer and colored solution above given will yield asafe and efficient developer, if the developing-tray is no larger than necessary to be half-filled by thcmixture; but the circumstances of the case and the experience of the operator will determine the depth of color in the mixture.

I hereby reserve the right to make future application for the non-actinie fiXiug-miiture hereinbefore referred to.

I claim as new and desire to secure by Let ters Patent 1. The combination, with a photographic developer, of a non-actinic inorganic coloringmatter, substantially as and for the purpose specified.

2. The combination, with a photographic developer, of a non-actinic aniline solution, substantially as and for the purpose specifled.

3. The combination, with a photographic developer, of orange aniline, substantially as IO and for the purpose specified.

Signed at New York, in the county of New York and State of New York, this 11th day of February, A. D. 1889.

CHARLES SPIRO. Vitnesses:

C. W. STUBBINGs, JOHN H. SCI-IULTE 

